An image processing device that is capable of performing image-read processing and image-print processing, such as a facsimile device, for example, typically comprises two types of platen roller. One such platen roller is an original-document platen roller that is for transporting an original document that has an image to be read, and that is actuated when image-read processing takes place. The other platen roller is a recording-paper platen roller that is for transporting recording paper which is to be subjected to print-processing, and that is actuated when image-print processing takes place. The use of separate drive sources for the rotation of each of these two platen rollers is unfavorable on account of the high costs involved. Consequently, some conventional image processing devices, as shown in FIG. 7, are constructed such that two platen rollers are rotated through the use of one drive source.
The conventional image processing device shown in FIG. 7 comprises an image-read head 80, an original-document platen roller P1 that is provided facing this image-read head 80, a print head 81, a recording-paper platen roller P2 that is provided facing this print head 81, and a drive mechanism 7 for drive-rotating the two platen rollers P1, P2.
The drive mechanism 7 comprises a single motor M1, a driving gear 84 provided on the drive shaft of motor M1, a large-diameter gear 85, two movable gears 71, 72, and intermediate gears Ga to Gf. The large-diameter gear 85 is caused to rotate by driving gear 84. The two movable gears 71, 72 are driven by engagement with large-diameter gear 85. Since displacement of movable gears 71, 72 is required, in addition to rotation of same, these can be displaced, in the circumferential direction of large-diameter gear 85 as respectively shown by arrows Na, Nb, by the movement of a mechanism beyond the view of the figure in which another motor (not shown) constitutes a drive source.
According to a constitution of this kind, engagement of movable gear 71 with intermediate gear Ga enables original-document platen roller P1 to rotate via intermediate gear Gb, and original document D is thereby transported. Meanwhile, engagement of movable gear 72 with intermediate gear Gc enables recording-paper platen roller P2 to rotate via intermediate gears Gc to Gf, and recording paper K is thereby transported. At the same time as movable gear 71 engages with intermediate gear Ga, movable gear 72 engages with intermediate gear Gc, and simultaneous rotation of original-document platen roller P1 and recording-paper platen roller P2 is possible. With regard thereto, when either one of movable gear 71 and movable gear 72 is moved away from either intermediate gear Ga or intermediate gear Gc, as shown by the virtual displacement lines in FIG. 7, either one of original-document platen roller P1 and recording-paper platen roller P2 can be rotated independently of the other. It thus becomes possible to perform read-processing of the image of original document D, and image-print processing on recording paper K, separately or simultaneously.
However, the conventional image processing device must also comprise a mechanism (not shown) for displacing movable gears 71, 72 as described above. Furthermore, in order to drive this mechanism, another motor (not shown) must be provided in addition to motor M1. In addition, since, in a conventional image processing device, an image-read head 80 and print head 81 are provided separately, an original-document print head and recording-paper print head, that are correspondingly provided, are arranged separately from another. As a result, in order to transmit the rotational force of the two movable gears 71, 72 to original-document platen roller P1 and recording-paper platen roller P2, respectively, it is necessary to respectively provide individual intermediate gear paths Ga to Gb and Gc to Gf.
As described above, conventionally, in order to realize selective drive of original-document platen roller P1 and recording-paper platen roller P2 by means of movable gears 71, 72, a plurality of mechanisms have been required for the device and, as a result, a multiplicity of gears. However, this has resulted in a cumbersome overall constitution of the device and high manufacturing costs.